The invention discloses a moisturizing emulsion and a preparation method thereof. The emulsion is prepared from multiple components including jojoba oil, Limnanthes Alba seed oil, trehalose, panthenol, astaxanthin, resveratrol, laminaria digitata extracts, tranexamic acid, grape seed extracts, chlorella extracts, matricaria recutita extracts, crithmum maritimum extracts, ectoin, acetyl hexapeptide-8, allantoin, bisabolol, dipotassium glycyrrhizinate, sweet orange peel extracts and the like. While the effects of deeply retaining water, moisturizing, nourishing and repairing the skin and the like are achieved, a self-protection barrier can be established for the skin, and various irritations of the external environment can be isolated. In addition, the moisturizing emulsion disclosed by the invention has high safety and stability, the preparation technology is simple, conditions are controllable, and the moisturizing emulsion can be popularized and applied on a large scale.